LAUSR

To analyze the contrast-enhanced ultrasound (CEUS) characteristics of pediatric patients with focal liver lesions (FLLs) and develop a pediatric liver CEUS criterion to improve the diagnostic performance of CEUS in differentiating pediatric benign and malignant liver lesions. Between March 2011 and May 2020, patients < 18 years who underwent CEUS were retrospectively evaluated. The CEUS characteristics of FLLs were analyzed. A pediatric liver CEUS criterion categorized as CEUS-1 to CEUS-5 was developed. The diagnostic performance of the criterion (i.e., sensitivity, specificity, PPV, and NPV) was assessed. Chi-square and Mann-Whitney tests were used. After exclusion, the study included 130 lesions (mean diameter, 7.1 cm; range, 0.8–17.0 cm) from 130 patients (mean age, 36.0 months; range, 0.03–204.0 months; 74 boys). Hyperenhancement with washout in patients < 5 years or with early washout (≤ 45 s) was used to predict hepatoblastoma, with a sensitivity and specificity of 90.7% (95% confidence interval [CI]: 77.9%, 97.4%) and 93.6% (95% CI: 84.3%, 98.2%), respectively. Peripheral discontinuous globular hyperenhancement was used to diagnose hemangioma, with a sensitivity and specificity of 84.6% (95% CI: 65.1%, 95.6%) and 100% (95% CI: 95.4%, 100.0%), respectively. The rates of malignancies within the pediatric liver CEUS-1, CEUS-2, CEUS-3, CEUS-4, and CEUS-5 categories were 0.0%, 0.0%, 5.6%, 50.0%, and 96.1%, respectively. Besides, the incidences of hepatoblastoma in pediatric liver CEUS-3, CEUS-4, and CEUS-5 were 5.6%, 16.7%, and 67.5%, respectively. The pediatric liver CEUS criterion is useful in differentiating benign focal liver lesions from malignancies, especially hepatoblastoma from hemangioma. • Hyperenhancement with washout in patients